Video narration
Kaagaz ki ek patti ko haath mein pakadkar, uske upar se phoonk maaro - woh neeche jaane ke bajay upar kyon uthti hai? Pehli nazar mein lagta hai ki phoonk kaagaz ko neeche dabaayegi. Lekin tumhari hawa kaagaz ke upar se tezi se guzarti hai. Is saral sthiti mein, jahan hawa tez behti hai, wahan dabaav kam hota hai. Neeche ki hawa utni tezi se nahi behti, isliye kaagaz ke neeche dabaav zyada rehta hai. Yahin baat palatti hai: phoonk kaagaz ko neeche nahi dhakelti; neeche ka zyada dabaav use upar uthata hai. Behti hawa ki gati aur dabaav ke is rishte ko Bernoulli siddhant kehte hain. Is udaharan mein hawa ki tez chaal ke saath dabaav ghatta hai. To kaagaz upar kyon uthta hai? Upar tez behti hawa ka dabaav ghatta hai, aur neeche ka zyada dabaav use upar utha deta hai - yahi is siddhant ka asar hai.